Days after horrified relatives learned that former workers at a historic black cemetery near Chicago allegedly dug up hundreds of bodies in a scheme to resell grave plots, relatives are learning that DNA likely won't help them find their loved ones. The piles of bones and deteriorated records may make identifying many remains impossible.

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"Identifying everyone would be a tremendous long shot," John Howard, president of the National Association of Medical Examiners, said this week.

Officials estimate that at least 300 of 100,000 graves were tampered with at the Burr Oak Cemetery in Alsip, Ill., which is the burial place several famous Americans including civil rights-era lynching victim Emmett Till. Four former workers are charged with dumping exhumed bodies in a deserted field the size of four square blocks in order to resell grave plots. Till's grave was not disturbed.

In the weeks since authorities announced the graveyard scheme thousands of relatives have flooded the cemetery looking for answers. Some, who knew exactly where their family member was buried, reported missing gravestones or unkempt plots — but many others couldn't figure out where the relatives were buried because the cemetery's records were in such disarray.

Forensic experts say it's possible to extract enough viable DNA from many of the skulls, teeth and large bones. But investigators warn that it may not do much good because in order to find matches, scientists would then also have to test relatives from all of those buried at Burr Oak.

"We would theoretically have to get families of all 100,000 people that are buried there (to provide DNA samples)," said FBI spokesman Ross Rice. "It's insurmountable almost."

But even if all families were tested, many of those buried were from the same family and the DNA collected may not clearly identify exactly which relatives the bones belong to.

There's also another wrinkle. Thousands of bones may be mixed together. Investigators say it may be impossible to sift through them to match them to specific people and return complete remains to a single grave.

"The family might want to know they have their Uncle Joe back in the ground in one place," said former New York City chief medical examiner Michael Baden, who helped identify the bodies of more than 1,000 people killed by Hurricane Katrina in 2005. "But if families think that every single bone can be identified, that's unrealistic."

Some experts believe the situation at Burr Oak is so unique that there are few comparable cases.

Investigators sifted through rubble only to find tiny bits of remains after the Sept. 11 attacks, but like a deadly plane crash, scientists could compare DNA results with a definite list of victims.

Baden said the situation at Burr Oak is reminiscent of the mass graves found after during the civil war in the former Yugoslavia in the 1990s. But in that case, investigators were able to identify many victims because remains were held together by clothing that family members recognized.

Some experts point to a case in Georgia seven years ago as similar to Burr Oak. A former crematory operator was accused of leaving more than 300 bodies to rot in piles. Even though the bodies were largely intact, at least a few were never identified.

Cook County Sheriff Tom Dart said that is some ways the challenges of identifying people after a plane crash pale in comparison to what investigators are facing at Burr Oak.

"We have no idea who was on this plane," said Dart. Authorities have found record books with missing or moldy pages, disintegrated file cards stuffed in rusty cabinets. In one drawer, investigators found an animal nest, woven together with tufts of gray fur and shreds of paper records.

Another looming issue is whether crime labs in Illinois and elsewhere have the capacity to handle such a glut of DNA tests. Many labs in the U.S. already have huge backlogs, often related to murder, rape and other pressing criminal cases.

"How many people in a DNA lab can be diverted (to the Burr Oak case) is the question," Baden said. "Three weeks from now, when medical examiners start asking, 'What about my homicide case?' priorities could become an issue."

Scientists are also worried that some of the remains may not have enough viable DNA, especially because the chemicals in embalming fluid can damage the genetic blueprint, Howard said.

Dozens of officers have been slowly walking Burr Oak's grounds, scouring for signs that would reveal a tampered grave. On Wednesday, Dart joined them and stumbled over a hole in the ground. Officers dug it up and found a simple grave marker for Veda Kaufman, who died in 1971.

"My God, we have tried everything humanly possible to give people answers," the sheriff said. "But when you deal with things like this are you ever going to be able to get complete answers and complete closure? No way."

Ralph Thompson Jr., whose mother, father and son are among six generations of family members buried at Burr Oak, is one of those relatives hoping for answers. But the self-described junkie for TV crime shows says he knows this is a case where the mysteries won't be solved so easily, and families may have to settle for a mass burial for their loved ones.

"TV is TV. We're always looking for a good ending," said Thompson, 41, of the Chicago suburb of Elgin. "But in real life this is a whole different ball game."